Battery charging based on cost and life

ABSTRACT

One embodiment of the present subject matter includes a system that includes a battery, an electric vehicle, the battery coupled to the electric vehicle to propel the electric vehicle, and a charging circuit to charge the battery. The embodiment includes a charging cost circuit to estimate a charging cost rate and to turn on the charging circuit. The embodiment also includes a timer circuit to provide a time signal to the charging cost circuit. The embodiment is configured such that the charging cost circuit is to turn on the charging circuit during a first time period in which the charging cost rate is below a first threshold until the battery reaches a first energy stored level, and to turn on the charging circuit during a second time period in which the charging cost rate is above the first threshold.

BACKGROUND

Charging the battery of an electric vehicle is expensive, and if it isdone improperly, can damage the battery. Systems and methods are neededto reduce the cost of battery charging while reducing battery damage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high level diagram of an electric vehicle, according to oneembodiment.

FIG. 2 is a diagram of an electrical vehicle charging system, accordingto one embodiment.

FIG. 3 is a block diagram of an article according to various embodimentsof the invention.

FIG. 4 is a method of charging a battery, according to one embodiment ofthe present subject matter.

FIG. 5 is a method of charging a battery to a first energy stored levelduring a first time period and charging the battery during a second timeperiod, according to one embodiment of the present subject matter.

FIG. 6 is a method of charging a battery during a second time period,according to one embodiment of the present subject matter.

FIG. 7 is a method of charging to a first energy stored level during afirst time period, and to a second energy stored level during a secondtime period, according to one embodiment of the present subject matter.

FIG. 8 is a method of charging a battery in the context of a chargingrate that varies up and down throughout the day, according to oneembodiment of the present subject matter.

FIG. 9 is a method according to one embodiment of the present subjectmatter.

FIG. 10 is a method of charging a battery to achieve a selected range,according to one embodiment of the present subject matter.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings that form a part hereof, and in which is shown by way ofillustration specific embodiments which may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention, and it is to be understood thatother embodiments may be utilized and that structural, logical andelectrical changes may be made without departing from the scope of thepresent invention. The following description of example embodiments is,therefore, not to be taken in a limited sense, and the scope of thepresent invention is defined by the appended claims.

The present subject matter provides systems and methods to charge abattery of a vehicle in a way that is adaptive to context. For example,in some parts of the world, electricity is less expensive during certaintime periods. For example, electricity can be less expensive duringnighttime, when less energy is being consumed due to lower airconditioning rates. This is an example time period, and others arepossible.

The present subject matter provides users with the ability to selectschedules to charge their vehicle in light of such varying rates. Forexamples, a user can charge their car to a regular capacity (e.g., 80%of capacity) or a regular energy stored rate (percent of capacity neededto store a set amount of energy increases over time) during times whenit is less expensive to purchase electricity. Users can optionallyselect to charge the car in excess of the regular amount, perhaps toaugment available driving range, in certain examples. In some instances,a user can select to charge to a regular rate before they sleep, and canwake up and select to charge in addition to the regular range as theyprepare for their day. These and other embodiments are discussed herein.

FIG. 1 shows a vehicle system 100, according to one embodiment of thepresent subject matter. In various embodiments, the vehicle 102 is anelectric vehicle and includes a vehicle propulsion battery 104 and atleast one propulsion motor 106 for converting battery energy intomechanical motion, such as rotary motion. The present subject matterincludes examples in which the vehicle propulsion battery 104 is asubcomponent of an energy storage system (“ESS”). An ESS includesvarious components associated with transmitting energy to and from thevehicle propulsion battery 104 in various examples, including safetycomponents, cooling components, heating components, rectifiers, etc. Theinventors have contemplated several examples of ESSs and the presentsubject matter should not be construed to be limited to theconfigurations disclosed herein, as other configurations of a vehiclepropulsion battery 104 and ancillary components are possible.

The battery includes one or more lithium ion cells in various examples.In some examples, the battery 104 includes a plurality of lithium ioncells coupled in parallel and/or series. Some examples includecylindrical lithium ion cells. In certain examples, the battery 104includes one or more cells compatible with the 18650 battery standard,but the present subject matter is not so limited. Some examples includea first plurality of cells connected in parallel to define a first brickof cells, with a second plurality of cells connected in parallel todefine a second brick of cells, with the first brick and the secondbrick connected in series. Some examples connect 69 cells in parallel todefine a brick. Battery voltage, and as such, brick voltage, oftenranges from around 3.6 volts to about 4.2 volts in use. In part becausethe voltage of batteries ranges from cell to cell, some instancesinclude voltage management systems to maintain a steady voltage. Someembodiments connect 9 bricks in series to define a sheet. Such a sheethas around 35 volts. Some instances connect 11 sheets in series todefine the battery of the ESS. The ESS will demonstrate around 385 voltsin various examples. As such, some examples include approximately 6,831cells which are interconnected.

Additionally illustrated is an energy converter 108. The energyconverter 108 is part of a system which converts energy from the vehiclepropulsion battery 104 into energy useable by the at least onepropulsion motor 106. In certain instances, the energy flow is from theat least one propulsion motor 106 to the vehicle propulsion battery 104.As such, in some examples, the vehicle propulsion battery 104 transmitsenergy to the energy converter 108, which converts the energy intoenergy usable by the at least one propulsion motor 106 to propel theelectric vehicle. In additional examples, the at least one propulsionmotor 106 generates energy that is transmitted to the energy converter108. In these examples, the energy converter 108 converts the energyinto energy which can be stored in the vehicle propulsion battery 104.In certain examples, the energy converter 108 includes transistors. Someexamples include one or more field effect transistors. Some examplesinclude metal oxide semiconductor field effect transistors. Someexamples include one more insulated gate bipolar transistors. As such,in various examples, the energy converter 108 includes a switch bankwhich is configured to receive a direct current (“DC”) power signal fromthe vehicle propulsion battery 104 and to output a three-phasealternating current (“AC”) signal to power the vehicle propulsion motor106. In some examples, the energy converter 108 is configured to converta three phase signal from the vehicle propulsion motor 106 to DC powerto be stored in the vehicle propulsion battery 104. Some examples of theenergy converter 108 convert energy from the vehicle propulsion battery104 into energy usable by electrical loads other than the vehiclepropulsion motor 106. Some of these examples switch energy fromapproximately 390 Volts to 14 Volts.

The propulsion motor 106 is a three phase alternating current (“AC”)propulsion motor, in various examples. Some examples include a pluralityof such motors. The present subject matter can optionally include atransmission or gearbox 110 in certain examples. While some examplesinclude a 1-speed transmission, other examples are contemplated.Manually clutched transmissions are contemplated, as are those withhydraulic, electric, or electrohydraulic clutch actuation. Some examplesemploy a dual-clutch system that, during shifting, phases from oneclutch coupled to a first gear to another coupled to a second gear.Rotary motion is transmitted from the transmission 110 to wheels 112 viaone or more axles 114, in various examples.

A vehicle management system 116 is optionally provided which providescontrol for one or more of the vehicle propulsion battery 104 and theenergy converter 108. In certain examples, the vehicle management system116 is coupled to vehicle system which monitors a safety system (such asa crash sensor). In some examples the vehicle management system 116 iscoupled to one or more driver inputs (e.g., an accelerator). The vehiclemanagement system 116 is configured to control power to one or more ofthe vehicle propulsion battery 104 and the energy converter 108, invarious embodiments.

External power 118 is provided to communicate energy with the vehiclepropulsion battery 104, in various examples. In various embodiments,external power 118 includes a charging station that is coupled to amunicipal power grid. In certain examples, the charging station convertspower from a 110V AC power source into power storable by the vehiclepropulsion battery 104. In additional examples, the charging stationconverts power from a 120V AC power source into power storable by thevehicle propulsion battery 104. Some embodiments include convertingenergy from the battery 104 into power usable by a municipal grid. Thepresent subject matter is not limited to examples in which a converterfor converting energy from an external source to energy usable by thevehicle 100 is located outside the vehicle 100, and other examples arecontemplated.

Some examples include a vehicle display system 126. The vehicle displaysystem 126 includes a visual indicator of system 100 information in someexamples. In some embodiments, the vehicle display system 126 includes amonitor that includes information related to system 100. Some instancesinclude one or more lights. Some examples include one or more lights,and the vehicle display system 126 in these embodiments includes theillumination and brightness of these lights. The vehicle managementsystem, in certain embodiments, coordinates the function of a chargestate circuit 106, and the charging coupler port 108, as pictured inFIG. 1. In certain instances, the charge state circuit 106, and thecharging coupler port 108 are part of the vehicle management system 116.In some of these instances, the lighting circuit 114 is part of thevehicle display system 126. In certain examples, the illuminatedindicator 116 of FIG. 1 is part of the vehicle display system 126.

FIG. 2 is a diagram of an electrical vehicle charging system 202,according to one embodiment. In various embodiments, the system includesan electric vehicle 204 and a battery 206 coupled to the electricvehicle to the electric vehicle 204 to propel the electric vehicle 204.Electric vehicles contemplated by the present subject matter includeground based vehicles, as well as aircraft and aquatic vehicles.

The illustration includes a charging circuit 208 to charge the battery206. This can include an external charging station that converts powerfrom a municipal power grid to power that can be stored in battery 206.This can additionally include charging converter onboard the electricvehicle that can take energy from a generally available outlet of amunicipal power grid (such as a National Electrical ManufacturersAssociation 5-15 outlet) and convert it to power storable in the battery206. Other configurations are possible.

Various examples include a charging cost circuit 212 to estimate acharging cost rate. In various embodiments, a charging cost rate is theinstantaneous cost of energy transfer. Cost rate is in cost per energytransferred over time (e.g., $0.06 United States Dollars per kilowatthour). The present subject matter is compatible with various ways ofmeasuring how much energy is consumed and how quickly it is beingconsumed.

In various examples, the charging cost circuit 212 can control thecharging circuit 208 and turn it on or off. In various embodiments, thisincludes interrupting a conductive path to the charging circuit 208,such as by opening a switch. In additional instances, this includescommunicating a charging state signal indicative of whether the chargingcircuit 208 should be active or inactive. For example, in certainexamples, a field effect transistor switches activation power to thecharging circuit 208, and the charging cost circuit 212 controls thegate for the field effect transistor.

In some embodiments, the charging cost circuit 212 is part of a computeronboard a vehicle (e.g., the vehicle management system 116 of FIG. 1).In additional examples, the charging cost circuit 212 is part of acomputer in a home or workplace that at least partially controls how theelectric vehicle 204 is charged. Various embodiments include a timercircuit to provide a time signal to the charging cost circuit. The timer210 can be integrated with an electronics module, such as an assemblyincluding a printed circuit board, the timer, and the charging costcircuit.

In various examples, the charging cost circuit 212 is to turn on thecharging circuit 208 during a first time period in which the chargingcost rate is below a first threshold. In certain instances, the chargingcircuit 208 is turned on until the battery reaches a first energy storedlevel (e.g., a specified amp-hours amount, coulomb amount, etc.). Insome optional embodiments, the charging cost circuit 212 turns on thecharging circuit 208 during a second time period in which the chargingcost rate is above the first threshold. This might be during themorning, after a power supplier has switched to a higher cost rate, butbefore a user begins to drive their electric vehicle.

In various examples, the system includes a cost estimator circuit tocalculate total charging cost during the first period and the secondperiod. For example, this circuit can estimate that it will cost $5.00to charge an electric vehicle based on measured conditions andoptionally learned conditions. In certain examples, an electric vehiclecharging system monitors energy use patters to estimate total chargingcost. In additional embodiments, an electric vehicle charging systemcross references measured variables (such as voltage, temperature, andthe like) with known values to estimate total charging cost. Some ofthese examples include a trend circuit to record a plurality of chargingstop times over a period of days, and to predict a predicted chargingstop time based on the plurality of charging stop times. A charging stoptime, in various embodiments, is the time of day when a user usuallyunplugs their electric vehicle. In many cases, this is right before theuser engages their electric vehicle for a drive.

In some examples, the charging cost circuit 212 automatically selectsthe length of the second time period to achieve a reduced charging costthat is less than a total charging cost. For example, if an electricvehicle charging system estimates a total charging cost as set outabove, it can monitor charging cost rates and adjust time spent chargingduring a less expensive rate and time spend charging during a moreexpensive rate, such that the day's predicted cost of charging is lessthan the total charging cost that was estimated.

If desired, certain embodiments include a user controllable interfaceconnected to the charging cost circuit 212 such that the user can inputa threshold for what is a less expensive charging cost rate and what isa more expensive charging cost rate. For example, in certainembodiments, a user could specify to charge only when below a certainthreshold by interacting with a computer (e.g., a vehicle computer or ahome computer).

In some examples, the present system is also aware of how calendar lifeis being impacted by charging behaviors. This can be studied usingmonitored variables (e.g., by performing a load test) or by monitoringcharging behavior over time (e.g., counting the number of cycles andmonitoring cycle parameters such as current rate and time duration). Thesystem can prioritize whether charging is selected to improve calendarlife or reduce cost. For example, some instance charge a battery to aregular energy stored level, such as 80% of full stored energy,preferentially to improve calendar life, as certain battery chemistries,such as lithium ion, last longer if they are charged as such. Someexamples will not charge above a regular energy stored level unlessinstructed to. Instruction can be in the form of an indicator, such as asignal from a computer that automatically provides the signal based onan analysis, or it can be provided based on a manual interaction with auser. For example, an electric vehicle can be adjusted so that it isalways in “regular mode” in which it charges to 80% of full storedenergy for most of its life, and is only charged to “boost mode” (e.g.,90% of full stored energy level) when a user or other source instructsit to do so.

As such, in certain examples, the charging cost circuit 212 is to turnon the charging circuit until the battery reaches a second energy storedlevel. The second energy stored level can be between a first energystored level and a full energy stored level, or it can be at a fullenergy stored level. The present subject matter includes embodiments inthat a charge is held at the second energy stored level for a period oftime. For instance, if a first time period is specified in which a firstenergy stored level can be reached, and a second time period isspecified in which a second energy stored level can be reached, thepresent system can reach the first energy stored level and pause untilit enters the second time period, and then charge until the secondenergy stored level is reached. If the second energy stored level isreached before expiration of the second time period, the present systemcan maintain the second energy stored level. A user controllableinterface is included in some examples and is connected to the chargingcost circuit 212 such that the user can input length of the secondperiod during which charging takes place.

Hardware and Operating Environment

This section provides an overview of example hardware and the operatingenvironments in conjunction with which embodiments of the inventivesubject matter can be implemented.

A software program may be launched from a computer-readable medium in acomputer-based system to execute functions defined in the softwareprogram. Various programming languages may be employed to createsoftware programs designed to implement and perform the methodsdisclosed herein. The programs may be structured in an object-orientatedformat using an object-oriented language such as Java or C++.Alternatively, the programs may be structured in a procedure-orientatedformat using a procedural language, such as assembly or C. The softwarecomponents may communicate using a number of mechanisms well known tothose skilled in the art, such as application program interfaces orinter-process communication techniques, including remote procedurecalls. The teachings of various embodiments are not limited to anyparticular programming language or environment. Thus, other embodimentsmay be realized, as discussed regarding FIG. 3 below.

FIG. 3 is a block diagram of an article 300 according to variousembodiments of the present subject matter. Such embodiments may comprisea computer, a memory system, a magnetic or optical disk, certain otherstorage device, or any type of electronic device or system. The article300 may include one or more processor(s) 306 coupled to amachine-accessible medium such as a memory 302 (e.g., a memory includingelectrical, optical, or electromagnetic elements). The medium maycontain associated information 304 (e.g., computer program instructions,data, or both) which, when accessed, results in a machine (e.g., theprocessor(s) 306) performing the activities described herein.

Methods

Various methods disclosed herein provide for battery charging based oncost and life. As mentioned above, certain examples charge batterieswith electricity derived from a municipal power grid. In some instances,this electricity is less expensive during certain times of the day. Inparticular, many parts of the world offer less expensive energy duringevening times. The present subject matter provides methods that canautomatically charge a vehicle in consideration of such less expensivecharging cost rates. The present subject matter, however, is alsofunctional under a manual operation scheme, in which a person is able toselect an amount of energy to receive during a first period of time(e.g., a period of time when electricity is less expensive), and duringa first period of time (e.g., a period of time when electricity is moreexpensive).

FIG. 4 is a method of charging a battery, according to one embodiment ofthe present subject matter. At 402, the method includes determiningcharging cost rate. At 404, the method includes charging a battery of anelectric vehicle to a first energy stored level while a first chargingcost rate is determined. At 406, a decision is made: should the systemcharge to a second energy stored level? If yes, at 408, the systemcharges the battery to a second energy stored level while a secondcharging cost rate is determined that is higher than the first energystored level. If no, the method ends. Various optional features arecombinable with the present methods. For example, in certain optionalmethods, the first charging cost rate is lower than the second chargingcost rate. But some methods are contemplated in which the first chargingcost rate is higher than the second charging cost rate.

Various options are contemplated. As stated elsewhere, examples in whicha system does not charge fully, but will charge more fully wheninstructed to, are contemplated. In certain embodiments, if a user plugsin their electric vehicle at night, it will charge to a first energystored level and pause at that level. In some embodiments that level is80% of capacity, but the present subject matter is not so limited. Incertain examples, unless the user instructs the electric vehicle tocharge even more, the vehicle will not charge more. In certaininstances, a push button is provided in an electric vehicle chargingsystem that enables a user to instruct the system to add more charge.Such a push button could be operated in the morning, in some instances,shortly before a user realizes they should use their car to drive longerdistances before recharging than normal.

In some embodiments, a system is provided that is able to store abattery at a energy stored level that improves calendar life. In certainexamples, this energy stored level is 50% of capacity. This energystored level can be monitored over time and maintained. The storedenergy level maintenance mode is entered into upon a user input, in someexamples. In additional embodiments, a vehicle realizes that it has beendormant for a period of time that exceeds a threshold, and enters astorage mode. Various examples recognize dormancy in other ways, such asby monitoring the odometer or reading other instruments. Storage modecan be indicated by a horn sound or with another indicator, such as aflashing light.

FIG. 5 is a method of charging a battery to a first energy stored levelduring a first time period 504 and charging the battery during a secondtime period 506, according to one embodiment of the present subjectmatter. Illustrated is an example in which a battery is charged untilthe first energy stored level 502 is reached. In various embodiments,this charging is limited to a first time period 504. In variousexamples, the first time period is coincident with the time of day inthat a first charging cost rate is within in a first cost range.

Additional embodiments charge the battery until the second energy storedlevel 508 is reached. In various examples, this occurs during a secondtime period 506. In certain instances, the second time period 506 isuser selected. In some embodiments, the second time period 506 iscoincident with a period of time in which a charging cost rate fits intoa second cost range that is different from a first cost range. Incertain examples, the second energy stored level 508 is less than a fullenergy stored level. The illustrated embodiment shows that the electricvehicle was unplugged shortly before it reached the second energy storedlevel 508. This may be exhibited in examples in which a user decides toleave before the second time period ends.

FIG. 6 is a method of charging a battery during a second time period,according to one embodiment of the present subject matter. Embodimentsof the present subject matter include charging the battery to the secondenergy stored level only if so instructed by a stored indicator, asdiscussed above.

Some examples include predicting a daily charge stop time 602 based onan energy usage pattern. Some instances prompt a user to select betweenimproved calendar life and reduced cost. Embodiments that prompt a userfor information include storing a user response as the stored indicator.In various examples, if the stored indicator indicates improved calendarlife, the method charges to the second energy level by delaying chargingto the second energy level until charging can occur constantly up to thepredicted daily charge stop time such that the second energy storedlevel is reached. The present illustration shows that the battery of anelectric vehicle was already charged near a regular stored charge, andelected to not charge the battery during the first time period. Theelectric vehicle charging system additionally recognized a charge stoptime, and commenced charging such that it could reach the second energystored level 604 at the charge stop time 602. Such a system can improvecalendar life of a battery. Various embodiments include electing to notcharge to the second energy stored level.

FIG. 7 is a method of charging to a first energy stored 710 level duringa first time period, and to a second energy stored 712 level during asecond time period, according to one embodiment of the present subjectmatter. Various embodiments include charging the battery according to acharging schedule that includes a first time period 702 and a secondtime period 704, the first energy stored level 710 reached (during the ωtime period) within the first time period 702, the second energy storedlevel 712 (during the η time period) reached during the second timeperiod 704.

Some examples include predicting a daily cost based on an energy usagepattern. Some instances adjust the length of the first time period andlength of the second time period such that a total cost of charging tothe second energy stored level is less than the predicted daily cost.

Some examples include predicting a daily charge stop time 706 based onan energy usage pattern. Some of these examples include delaying (duringthe μ time period) charging to the second energy level until chargingcan occur constantly up to the predicted daily charge stop time 706. Insome instances, this occurs such that the second energy stored level 712is reached. Embodiments are included in which no charging occurs duringat least a portion of the second time period 704.

FIG. 8 is a method of charging a battery in the context of a chargingrate that varies up and down throughout the day, according to oneembodiment of the present subject matter. A charge rate 802 isdetermined and varies. A battery energy stored level 804 is charted inthe illustration. In various embodiments, if the charging rate is at afirst charge cost rate 806, the battery charges on its way to a firstenergy stored level 810. If the system reaches this level, it stopscharging if it is during the first time period. For example, a firsttime period, defined by the addition of time periods θ, α, and β isillustrated. During this time, the system charges only when the chargingcost rate is within the first charging cost rate range 806. Startingafter time period β, the illustration enters a second time period inwhich it is acceptable to charge as the second charging cost rate range808. The illustration reaches a second stored energy level 812, and doesnot add more charge during the γ time period, during that the secondcharging cost rate is realized, nor after that time period, during whichthe first charging cost rate is realized.

Such a system could be helpful in areas in which municipal power gridpricing fluctuates frequently, such as in areas where wind turbinesproduce excess power at windy times, and a shortage of power duringtimes in which it is not windy. Various examples include receiving acost signal and charging at one of the first charging cost rate and thesecond charging cost rate in response to that cost signal.

FIG. 9 is a method according to one embodiment of the present subjectmatter. At 902, the method includes storing a user selected drivingrange for an electric vehicle. At 904, the method includes determining apotential driving range based on a pattern of driving ranges achieved bycharging a battery of the electric vehicle to a first percentage ofcapacity. At 906, the method includes determining whether a first amountof energy stored when the battery is charged to the first percentage ofcapacity is sufficient to achieve the user selected driving range basedon the pattern of driving ranges achieved. At 908, the method includescharging the battery to the first percentage of capacity if the firstamount energy stored is sufficient to power the electric vehicle throughthe selected driving range. At 910, the method includes charging thebattery to a second percentage of capacity, which is higher than thefirst percentage of capacity, if the first energy stored is notsufficient to power the electric vehicle through the user selecteddriving range. In certain examples, the second energy stored level is100%.

FIG. 10 is a method of charging a battery to achieve a selected range,according to one embodiment of the present subject matter. A life cycleof a battery always charged to a regular capacity 1002 is illustrated,with a regular end of life 1010. This is the energy stored when thebattery is charged to a specific capacity, such as 80%, that is lessthan full capacity. Additionally illustrated is a life cycle of abattery always charged to a full capacity 1004, with a full end of life1006. A hybrid curve 1012 is illustrated for a battery which is at firstcharged to a regular capacity, and then to a capacity that is more thanthe regular capacity, demonstrating a hybrid end of life 1008. In theillustration, the hybrid begins to charge a battery at a capacity higherthan a regular capacity starting at a certain time 1014, although thepresent subject matter is not so limited. The time hybrid starts tocharge to a capacity in excess of the regular capacity commences cancoincide with the time that energy stored when charged to regularcapacity starts to diminish. The penalty for charging the hybrid higherthan the regular capacity is an earlier end of life 1008 than the end oflife 1010 enjoyed by batteries always charged to regular capacity.Battery capacity has a linear relationship with voltage in someexamples, and certain instances charge to respective voltages in certainexamples.

The hybrid curve assists in a user to consistently maintain a usabledriving range. For example, if energy stored for a certain capacitystarts to diminish, as it does for the regular capacity curve 1002 aftera certain time 1014, driving range for that capacity also diminishes.But some users desire to avoid diminished range. As such, the presentsubject matter charges to a higher capacity, following the hybrid curve1012. This provides a compromise between enjoying some time during whicha longer range is realized, and shortening the end of life of thebattery.

Various examples of the present subject matter automatically trackdecreasing range based on an energy use pattern. Some of theseembodiments switch to a hybrid curve automatically, so a user does notrealize range is decreasing. In some embodiments, switching to thehybrid curve occurs only if the end of life is predicted to occur withinthe warranty period of an electric vehicle. Some embodiments provide analert to a user than charging to a hybrid capacity has begun. In someinstances the hybrid curve includes a series of incremental upwardadjustments to capacity. In some embodiments, capacity is increased by0.05% a day. Other increases are contemplated.

In some embodiments, a vehicle system drives a first range during somedriving sessions and a second range during additional driving sessions,and a user selects which range to drive. In some of these embodiments, avehicle charging system automatically selects which of the regularcapacity and the hybrid capacity to use depending on the user selectedrange.

The Abstract is provided to comply with 37 C.F.R. §1.72(b) to allow thereader to quickly ascertain the nature and gist of the technicaldisclosure. The Abstract is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims.

1. A method of charging a battery within an electric vehicle utilizing abattery charging system, the method comprising the steps of:continuously determining an instantaneous charging cost rate, whereinsaid instantaneous charging cost rate is continuously determined as afunction of time; determining a charging schedule that includes at leasta first time period and a second time period, wherein said first timeperiod precedes said second time period, and wherein a charging stoptime is anticipated to occur within said second time period; initiatingbattery charging within said first time period whenever saidinstantaneous charging cost rate is less than a threshold cost rate;pausing battery charging within said first time period whenever saidinstantaneous charging cost rate is greater than said threshold costrate; resuming battery charging within said first time period wheneversaid instantaneous charging cost rate is less than said threshold costrate; terminating battery charging within said first time period aftersaid battery reaches a first energy stored level; initiating batterycharging within said second time period regardless of said instantaneouscharging cost rate; and terminating battery charging within said secondtime period after said battery reaches a second energy stored level,wherein the second energy stored level is higher than the first energystored level.
 2. The method of claim 1, wherein the second energy storedlevel is less than a full energy stored level.
 3. The method of claim 1,wherein said step of initiating battery charging within said second timeperiod is only performed in response to a stored indicator.
 4. Themethod of claim 1, further comprising: predicting a daily cost based onan energy usage pattern; and adjusting the length of the first timeperiod and length of the second time period to minimize the predicteddaily cost.
 5. The method of claim 1, further comprising: predictingsaid charge stop time based on an energy usage pattern; and determininga start time for performing said step of initiating battery chargingwithin said second time period, wherein said start time is selected toallow said second energy stored level to be reached prior to occurrenceof said charging stop time.
 6. The method of claim 5, wherein nocharging occurs during at least a portion of the second time period. 7.The method of claim 1, wherein said step of continuously determiningsaid instantaneous charging cost rate further comprises the step ofreceiving charging cost rate from a municipal power grid.
 8. The methodof claim 1, further comprising the steps of programming said chargingstop time within said battery charging system and determining a starttime for performing said step of initiating battery charging within saidsecond time period, wherein said start time is selected to allow thesecond energy stored level to be reached before the charge stop time. 9.The method of claim 1, further comprising the steps of: monitoring adaily charging system termination time; and estimating said chargingstop time based on results of said monitoring step; and determining astart time for performing said step of initiating battery chargingwithin said second time period, wherein said start time is selected toallow the second energy stored level to be reached prior to occurrenceof said charging stop time.
 10. The method of claim 1, furthercomprising the step of setting said second energy stored level to 100%energy capacity.
 11. The method of claim 1, further comprising the stepsof monitoring a plurality of charge cycles, and increasing said secondenergy stored level based on results of said monitoring step.
 12. Themethod of claim 11, wherein said monitoring step further comprises thestep of monitoring driving range over time and wherein said step ofincreasing said second energy stored level further comprises settingsaid second energy stored level to maintain a predetermined drivingrange.
 13. A battery charging system, comprising: a battery; an electricvehicle, the battery coupled to a propulsion motor configured to propelthe electric vehicle; a charging circuit to charge the battery; a timercircuit outputting a plurality of timing signals corresponding to atleast a first time period and a second time period, wherein said firsttime period precedes said second time period; a charging cost circuit,wherein said charging cost circuit controls operation of said chargingcircuit and receives said plurality of timing signals from said timercircuit, wherein said charging cost circuit continuously monitors aninstantaneous charging cost rate, wherein said charging cost circuitinitiates operation of said charging circuit during said first timeperiod whenever said instantaneous charging cost rate is below athreshold cost rate, pauses operation of said charging circuit duringsaid first time period whenever said instantaneous charging cost rate isabove said threshold cost rate, resumes operation of said batterycharging circuit during said first time period whenever saidinstantaneous charging cost rate is less than said threshold cost rateand terminates operation of said charging circuit during said first timeperiod when said battery reaches a first energy stored level, andwherein said charging cost circuit initiates operation of said chargingcircuit during said second time period regardless of said instantaneouscharging cost rate and continues operation of said charging circuituntil said battery reaches a second energy stored level or operation isdisrupted by a system user, wherein said second energy stored level isgreater than said first energy stored level.
 14. The battery chargingsystem of claim 13, further comprising a trend circuit to monitor aplurality of daily charging system termination times, said trend circuitdetermining a charging stop time based on said plurality of dailycharging system termination times, wherein the charging cost circuitdetermines a charging circuit initiation time within said second timeperiod to achieve said second energy stored level prior to reaching saidcharging stop time.
 15. The battery charging system of claim 13, furthercomprising a user controllable interface connected to said charging costcircuit such that a user can input said threshold cost rate.
 16. Thebattery charging system of claim 13, further comprising a usercontrollable interface connected to said charging cost circuit such thata user can input a charging stop time, wherein the charging cost circuitautomatically selects a charging circuit initiation time within saidsecond time period to achieve said second energy stored level prior toreaching said charging stop time.
 17. The battery charging system ofclaim 13, wherein said second energy stored level is less than a fullenergy stored level.
 18. The battery charging system of claim 13,further comprising a user controllable interface connected to thecharging cost circuit such that a user can input a charging circuitinitiation time within said second time period.
 19. The battery chargingsystem of claim 13, further comprising a user controllable interfaceconnected to the charging cost circuit such that a user can input alength of time for said first time period.
 20. The battery chargingsystem of claim 13, wherein said first energy stored level is 80% offull stored energy.
 21. The battery charging system of claim 13, whereinsaid second energy stored level is 90% of full stored energy.
 22. Thebattery charging system of claim 13, wherein said charging cost circuitreceives a municipal charging cost rate from a power network andestimates said instantaneous charging cost rate based on said municipalcharging cost rate.